1. What have the authors contributed in "Sampled-data supervisory control" ?
In this thesis, the authors identify a set of existing TDES properties that will be useful to their work, but not sufficient.. The authors then establish a formal representation of an SD controller as a Moore Finite State Machine ( FSM ), and describe how to translate a TDES supervisor to a FSM, as well as necessary properties to be able to do so.. The authors discuss how to construct a single centralized controller, as well as a set of modular controllers and show that they will produce equivalent output.. Next, the authors capture the enablement and forcing action of a translated controller in the form of a TDES supervisory control map, and show that the closed-loop behavior of this map and the plant is the same as that of the plant and the original TDES supervisor.. The authors also show that their method is robust with respect to nonblocking and certain variations in the actual behavior of their physical system.. The authors also introduce a set of predicate-based algorithms to verify the SD controllability property, as well as certain other conditions that they require.. The authors have created a software tool for verifying these conditions and provide the source code in the appendix.. For illustrative purpose, the authors have produced a set of examples which fail the key conditions discussed in this thesis, as well as a successful application example based on a Flexible Manufacturing System.. The authors also presented the corresponding FSM,
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2. What future works have the authors mentioned in the paper "Sampled-data supervisory control" ?
1. However, the authors only partly dealt with time delay issues which they have left as future work due to time considerations.. The authors have tried to mitigate potential time delay problems by the assumptions they have made at the beginning of Chapter 3.. Another potential time delay problem is the difference between when an event physically occurs ( say a part arrives at a machine ), and when a controller sees that the event has occurred.. By the properties defined in Chapter 3, an SD Controller can be modeled as a Moore machine.
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